Matching industrial networks to hardware

Oct. 28, 2019
Getting industrial instrumentation to operate effectively on office networks can be frustrating, but WirelessHART can help

There are many situations in pharmaceutical manufacturing where scientists and engineers must do their development and production work in office-type environments. Most often, these situations occur in locations such as laboratories or other R&D sites where industrial equipment needs to operate, but without the infrastructure support found in process plants. It is in these environments, device-level industrial networks supported by wireless instrumentation can make a significant impact.

Creating and collecting process data such as temperature, pressure, flow and level via process instrumentation during development and production is a key operating requirement. Measurement devices quantify their respective variables and send the data to a monitoring or automation system. The data is then delivered using communication protocols that are a mix of current or voltage analog and digital signals. These protocols can be unfamiliar to office IT network administrators as they are not commonly based on Ethernet, which is often the only type of networking technology supported by IT in those environments. 

As a result, building a device-level network to communicate with a variety of field instruments in low-density, non-industrial environments can be more challenging than automating a large refinery or chemical plant. Trying to perform the task using what is effectively office IT network technology is difficult considering factors such as the layout of the space, required operational flexibility and a lack of necessary tools. For effective data collection, process instrumentation needs industrial networks.

Pharma R&D facilities range in size from modest plants to sprawling campuses where newly discovered products are analyzed prior to upscaling for commercial production. In large facilities, there can be dozens of individual laboratories running experimental batches of new products with small-scale equipment. The data from these batches needs to be collected thoroughly and efficiently for product analysis, and to support product technology transfer when advancing to full-scale production runs.

Each lab needs to have whatever equipment is necessary for the specific product, so a common practice is to make larger pieces moveable. This allows them to be relocated as necessary to accommodate the requirements for any given project. Small setups may call for very simple experiments with few instruments, but larger operations require several more complex experiments and associated process measurement and data capture. Therefore, a device-level network is required to support hundreds of potential instruments in individual labs across the facility, and to enable the flexibility of moving many of these instruments from place to place as process changes occur.

Using office IT architecture

A common practice is to deploy a remote I/O station in every lab, each capable of supporting the variety of field instruments connected to it. These stations can be tied together using wired Ethernet via the business local-area network (LAN). IT administrators often set these up in a virtual LAN within the office system with fixed IP addresses along with a floating domain name system. 

The network funnels information from the various labs to a central collection point where data is archived so scientists and engineers can analyze each experimental run. Where processes need external control, the network includes a process automation host system. This approach can work, but because the basic infrastructure is not designed for industrial applications, it may result in several reoccurring issues, as many of Emerson’s pharmaceutical clients have observed: 

• When IT technicians need to apply a patch, install an upgrade, move an address or perform other related office functions, they typically ping the relevant switch. This often causes a one-scan failure with the instruments, which results in a data loss covering several seconds. To the scientist running the experiment, such gaps can be very serious.

• Technicians responsible for overseeing specific experiments usually receive alarms via their smartphone if a variable moves out of range. Patches and other IT-related network disruptions can sometimes create alarm floods, indiscriminately overwhelming the support team and disrupting data collection.

• Technicians working on equipment supported by the business LAN do not always have access to tools common with industrial networks. Device calibration becomes far more complicated, and configurators for basic instrumentation maintenance functions, such as lead compensation for resistance temperature devices (RTDs), are probably not available. Creating workarounds to overcome these problems adds time and complexity.

• If the network needs to expand, adding new I/O via the wired LAN is very expensive. Extending wired connections can easily cost as much as $100 per foot.

One solution to overcome these problems is to simply provide an automation system and data historian for each lab, but this approach is complex to deploy and very expensive. Moreover, it makes setting up a new experiment much more labor-intensive. Fortunately, there is a better way to communicate using an industrial network designed specifically for process instrumentation yet easily deployable in an office environment.

Adding a wireless network

Wireless Ethernet (Wi-Fi) may seem an obvious choice, but for process instrumentation, Wi-Fi is really little better than traditional wired Ethernet. It may reduce installation costs for a new I/O station but does not solve the other problems associated with IT networks. The answer is to choose a wireless network designed specifically for instrumentation: WirelessHART.

WirelessHART is a self-organizing mesh network consisting of individual field instruments and a gateway. It is the most widely deployed device-level networking protocol with dozens of compatible devices available from a wide range of manufacturers.

The wireless field devices have self-contained power modules and communicate with one another and the gateway. The gateway then provides a hardwired connection to the automation host system, asset management, monitoring and/or data analytics environment. Data from the field devices moves to the gateway, which is normally connected to the larger corporate IT network infrastructure via a wired Ethernet connection. The data can then be securely accessed anywhere, ranging from an individual production unit’s host system all the way to a cloud environment. 

WirelessHART is designed to work in industrial environments, but can it operate effectively in the more office-like space of an R&D facility? And is it practical to use where legacy Ethernet systems are already installed?

For these situations, companies using WirelessHART usually find some pleasant surprises. Radio propagation in typical R&D buildings is very effective and is much like Wi-Fi. If Wi-Fi networks work well, WirelessHART will also. It has a strong ability to penetrate through floors and walls, and coverage can be verified using standard network diagnostic tools to measure signal strength and indicate how mesh networks form.

WirelessHART gateways can be installed as needed throughout the facility to provide 100 percent coverage and deliver instrumentation data directly to host systems, avoiding problems introduced by office IT networks.

Beginning a migration

One of the attractive aspects of this approach is its scalability. A migration can be approached incrementally, accommodating experimentation as managers gain familiarity and get comfortable with the concepts.

A typical starting point can be monitoring temperature sensors attached to coolers and freezers. Each unit can have a WirelessHART transmitter attached that connects to the internal temperature sensor, typically an RTD or a thermocouple. If a large unit has multiple internal sensors, there are WirelessHART transmitters available that can send data from up to four individual sensors on one multiplexed signal. If these coolers need to be moved around the facility, they will join the network automatically wherever they go.

Over time, the facility can increase the number of WirelessHART transmitters, expanding the range of variables measured and applications. A larger population also increases the strength of the network with more communication points.

Effective diagnostic tools

Prospective users are often concerned about security and the management of WirelessHART networks, but they are reassured when they find the range of diagnostic tools available. For example, Emerson’s AMS Wireless Snap-On can fill many of the gaps they are trying to bridge with Ethernet LAN workarounds:

• The tool is the main mechanism for adding new devices to the network. When a new instrument is added, connecting it to the main engineering station with a USB cable provides the means to set the network ID and join key to add the instrument within the security protocol.

• The tool monitors network performance. The Snap-On includes a detailed floor plan of the facility, showing the locations of all the devices on the network. It is a simple matter to see how signals are propagating, how various devices are meshing and how the entire network is organized.

• Diagnostic information from smart field instruments can warn of any developing equipment problems, down to the remaining battery life of any self-powered instrument on the network. The information is very visual in its basic presentation, but technicians can drill down to extensive detail when necessary.

• Industrial-strength calibration and configuration tools are available to eliminate the cumbersome workarounds and manual steps necessary with an Ethernet LAN system.

Implementation strategies

Facilities that have adopted WirelessHART generally use it alongside existing Ethernet LAN networks. Where the LAN is performing effectively, it can be left in place. WirelessHART becomes the go-to approach for new installations, and in instances where the LAN’s problems are particularly acute. Even with two networks operating in parallel, most facilities find a reduction in maintenance costs.

As a less intrusive, less expensive yet more robust alternative to office IT LANs, WirelessHART networks for process instruments provide the benefits of an industrial network in an office environment. It makes life for the scientist and support team far easier and their experimental efforts more efficient. 

About the Author

Jacob Smedsrud | Wireless Product Engineer